Hair clippers

ABSTRACT

A hair cutting machine ( 10 ) having a handle ( 12 ) that contains an electromotive drive unit ( 49 ) and having a cutter head ( 16 ) that is disposed at the front handle end and, in the operating position of the handle ( 12 ), has a stationary blade ( 18 ) and an oscillating blade ( 20 ) disposed above it, the stationary and oscillating blades ( 18, 20 ) forming a cutting plane ( 22 ) that lies between the two blades ( 18, 20 ) and is inclined in relation to the longitudinal axis ( 24 ) of the handle ( 12 ). In the operating position of the handle ( 12 ), the cutting plane ( 22 ) is inclined downward in relation to the longitudinal axis ( 24 ) of the handle ( 12 ) and the oscillating blade ( 20 ) is disposed above the stationary blade ( 18 ), which makes it possible to produce a haircut that is comparable to a classic scissors cut (FIG.  9 ).

The present invention relates to a hair cutting machine as genericallydefined by the preamble to claim 1.

CROSS-REFERENCE

The invention described and claimed hereinbelow is also described inPCT/DE 03/09131, filed on Aug. 18, 2003 and DE 102 38 335.9, filed onAug. 16, 2002. This German Patent Application, whose subject matter isincorporated here by reference, provides the basis for a claim ofpriority of invention under 35 U.S.C. 119 (a)-(d).

BACKGROUND OF THE INVENTION

The present invention relates generally to a hair cutting machine.

The best cutting results can generally be achieved with a pair ofscissors; but a scissors cut requires an extremely high degree of manualdexterity and takes a lot of time. The scissors cut can achieveparticularly harmonious transitions in the neck and side region. Sincethe scissors cut is comprised of numerous individual linear cuts, thisproduces a visual effect that is referred to as a soft haircut. In ahaircut using a hair cutting machine, however, numerous individual,oblong, flush cut surfaces are produced, yielding a stepped effect thatrequires a time-consuming finishing with thinning shears in order tocompensate for this stepped effect in a visually acceptable manner. Buteven with this additional measure, the result is nowhere near that of aclassic scissors cut.

The object of the present invention is to produce a hair cutting machinesimilar to the species, which improves the hair cutting results so thatthey are equivalent to the results of a classic scissors cut. Inaddition, from an ergonomic standpoint, it should be possible for a userto use the hair cutting machine without requiring a change in operation,thus allowing the user to operate it in the accustomed way.

SUMMARY OF THE INVENTION

With the handle of the hair cutting machine in the operating position,because the cutting plane is inclined downward in relation to thelongitudinal axis of the handle, with the oscillating blade disposedabove the stationary blade, the oscillating blade on the cutter head ofthe hair cutting machine is oriented so that the oscillating bladeproduces a vibrating action with approximately 25 to 50 oscillations persecond in order to continuously guide strands of hair into thestationary blade, which produces a fine, dense thinning of hair. Thisvibrating action of the oscillating blade is an additionalcharacteristic and an important component for achieving a cutting resultwith a hair cutting machine equal to that of a scissors cut.

One advantage of the hair cutting machine according to the presentinvention is that it can mechanically produce a haircut that gives avisual impression similar to that of the classic scissors cut withoutthe danger of injury to the scalp. Another essential advantage is thatthis hair cutting machine can produce a haircut in a significantlyshorter amount of time than a classic scissors cut, therefore alsoyielding economic advantages.

The hair cutting machine has the following advantages:

-   -   The risk of cutting bare patches and “holes” is reduced to the        greatest extent possible.    -   Ergonomic operation.    -   Reduced work time in comparison to a scissors cut.    -   The cut is clearly visible while working and the cutter can be        securely held.    -   Simple contour cutting without having to rotate the hair cutting        machine.

An exemplary embodiment of the present invention is shown in thedrawings and will be described in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 3 are schematic depictions for illustrating the cuttingtechnique of the classic scissors cut (prior art);

FIGS. 4 and 4 a are schematic depictions for illustrating the cuttingtechnique of a haircut using the known hair cutting machines (priorart);

FIG. 5 shows a perspective view of the hair cutting machine;

FIG. 6 shows a side view of the hair cutting machine with a cutter head;

FIG. 7 is a schematic view for depicting the angle of the cutting planein relation to the longitudinal axis;

FIG. 8 is a schematic view of the positioning of the hair cuttingmachine in relation to the scalp;

FIG. 9 shows how the hair cutting machine is guided;

FIG. 9 a shows the cutting results with the particular cuttingtechnique;

FIG. 10 schematically depicts the positive angle of the hair cuttingmachine in relation to the cut surface;

FIG. 11 schematically depicts the negative angle of the hair cuttingmachine in relation to the cut surface;

FIG. 12 schematically depicts a cutter head, which, due to the steeplyinclined positioning of the cutting plane in relation to the cutsurface, produces a thinned cutting result;

FIG. 13 schematically depicts a cutter head, which, due to the steeplyinclined orientation of the cutting plane in relation to the cutsurface, produces the flush cutting result;

FIG. 14 shows a perspective view of the cutter head with its individualparts, including the motor and drive shaft;

FIG. 15 shows a schematic side view of the drive shaft, stationaryblade, and oscillating blade, and

FIG. 16 shows the assembled cutter blade in which it is clear that themetal pin is guided through the stationary cutter blade and thenprotrudes into an indentation in the oscillating cutter blade.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 3 show a cutting technique using a pair of scissors 51. FIG.1 shows that the strands of hair 32 cut with the scissors 51 havedifferent lengths. This is intended to explain that a number of strandsof hair 32 are simultaneously cut horizontally at one point, i.e. thecut 30. Since the strands of hair 32 above and below the cut 30 are alonger distance from the cut 30 than the hair 31 is to the cut 30, thestrands of hair 32 remain longer than the hair 31 does from the cut 30.This is clearly depicted in FIG. 2 as a curved cut 33 in which thestrands of hair 32 are drawn uniformly away from the scalp 26. Amultitude of cuts 34 in succession yields a soft cut surface with smallsteps 35 so that the haircut can be referred to as soft (FIG. 3).

By contrast, a haircut using the hair cutting machine according toDE4317530 produces a flush cut since the strands of hair 32 arecollected by a stationary blade 18 parallel to the cut surface 36 andare cut off flush.

When performing a haircut, the short hair at the neck and the sides isthe hardest to work with in terms of cutting technique. The goal here isto produce a harmonious flow between the nape of the neck (hair length0%) and the longer hair above it (hair length 100%). The cut surface isinclined in relation to the scalp and is referred to below as aninclined cut surface. But an inclined surface is also produced when notransition is cut and the hair at the nape of the neck has a length of 1cm, for example, while the hair at the top of the head is 10 cm long,for example.

FIGS. 4 and 4 a show the cutting technique with a conventional haircutting machine 52. The hair cutting machine 52 is moved in a direction37 along the desired cut surface 36 from 0% to 100% of the desired hairlength L. This produces a hard, flush cut surface 36 without smallsteps, which gives the haircut an unharmonious look.

Is particularly difficult to guide the hair cutting machine 52,especially in the region of the nape of the neck, because a cutting comb53 can no longer be placed underneath it. In order to assist in cuttinghair, cutter attachments are often used, but these cannot be used toproduce an inclined cut surface 36. Instead, these cutter attachmentsmerely serve to prevent the machine from cutting undesirable steps andbare patches.

The hair cutting machine 10 according to FIGS. 5 and 6 has a handle 12with the top and bottom side 12 a, 12 b, which contains an electromotivedrive unit, and has a cutter head 16 disposed at the front handle end14, with the oscillating blade 20 disposed above the stationary blade18. With the positive-angle hair cutting machine 10, when the haircutting machine 10 is used in the usual flat operation, the angle (therelationship of the scalp 26 or the cut surface 28 to the cutting plane22) is steeper than with conventional hair cutting machine 52, whichimproves results, especially those of transition cuts, and, due to areduced error rate, makes it possible to work more quickly.

FIG. 7 shows the angular relationship between the cutting plane 22 ofthe two blades 18, 20 and the longitudinal axis 24 of the hair cuttingmachine 10; the angle Alpha is 0 to 90°, preferably 0 to 45°, and evenmore preferably 5 to 35°. In actual use, an angle Alpha of approximately30° has turned out to be optimal. The cutting plane 22 of the haircutting machine 10 is inclined downward U in relation to thelongitudinal axis 24. Since the oscillating blade 20 of the hair cuttingmachine 10 is disposed above the stationary blade 18 (FIG. 6), in thecase of an eccentric drive unit 54, a metal pin 43 (FIG. 15) isprovided, which is connected to an eccentric shaft 42 and a drive shaft41; this metal pin 43 is guided through the lower stationary blade 18via an opening 44 in order to be able to drive the upper oscillatingblade 20 via an indentation 45.

FIG. 8 shows the guidance of the hair cutting machine 10 to produce atransition from 0 to 100% of the desired hair length L. The inclined cutsurface is labeled with the reference numeral 28.

FIGS. 9 and 9 a show the particular cutting technique with the haircutting machine 10, which is guided away from cuts 39 along curved paths38. FIG. 9 a shows the cutting result. A cutting result similar to thatof a classic scissors cut is achieved, distinguished by a soft cutsurface with the small steps 35.

The difference between a hair cutting machine 52 (FIG. 11) with anegative angle 47 in relation to the cut surface 36—which is generallyknown—and a hair cutting machine 10 (FIG. 10) with a positive angle 48can best be seen when the longitudinal axis 24 is positioned vertically.If the oscillating blade 20 is disposed on the downwardly inclined sideof the cutter head 16, then it is a negative angle 47 because when thehair cutting machine 52 is used, the effects of this negative anglebecome apparent in that this results in an almost inevitably parallelcourse of the cutting plane 22 in relation to the cut surface 36 becausewhen the cutting plane 22 extends parallel to the cut surface 36, thestationary blade 18 collects the strands of hair flush to one anotherand immobilizes them, thus cutting them in a hard and/or smooth surface.If the moving blade 20 is disposed on top of the stationary blade 18,then it is a positive angle (FIG. 10) with all of the positivelydescribed advantages, for example the vibrating action (FIG. 12), inwhich, when cutting using the hair cutting machine 10 with a positiveangle, the hair 42 is cut with an effect similar to that of a scissorscut due to a minimal thinning 40.

The inventor has discovered that surprisingly, the cutting results aresignificantly better the more steeply the cutter head of the haircuffing machine, i.e. the cutting plane 22, is oriented toward the scalpsince the strands of hair are not collected flush to one another andthen cut, but instead, the rapid back-and-forth motion of theoscillating blade 20 first vibrates the hair (FIG. 12) when the machineis guided in the cutting direction 37. Only after the vibration does thestationary blade 18 collect the various strands of incoming hair, whichare then immobilized and cut. As a result of this vibration, the cutsurface 34 is clean, but the strands of hair are not cut flush; the hairis subjected to a minimal degree of thinning 40, which approximates theeffect of a scissors cut.

In order to achieve a positive angle with a hair cutting machine, theoperator can in fact rotate a conventional hair cutting machine by 180°around the longitudinal axis, but the vibrating action is not producedsince the stationary blade collects and immobilizes the hair first sothat no thinning can occur. There is also a danger of injury to thescalp since, the oscillating blade is oriented toward the scalp in thisposition. In addition, the hair is only poorly collected andinsufficiently cut.

Another possibility is to rotate the hair cutting machine around thelateral axis in order to achieve a steeper alignment of the cuttingplane in relation to the scalp. But holding the hair cutting machine atthis angle requires the operator to keep it in an ergonomicallyunaccustomed position, which results in rapid fatigue.

The hair cutting machine according to the present invention achieves anoutstanding cutting result in a position that is ergonomically favorablefor the operator and does not involve the risk of injuring the scalp.

FIG. 10 shows the positive angle 48 of the hair cutting machine 10 whenthe longitudinal axis 24 is lifted 11 away from the cut surface 34; thecutter head 16 maintains its position spaced apart from the cut surface34 and the cutter head 16 is oriented more steeply in relation to thecut surface 34. The oscillating blade 20 disposed on top initiallyvibrates the strands of hair 32 before they are held and cut once thestationary blade 18 immobilizes them.

FIG. 11 shows the negative angle 47 of the cutting plane 22 in relationto the cut surface 36. As soon as the user lifts 11 the longitudinalaxis 24 in order to cut in the direction of the cut surface 36, thisautomatically produces a parallel, which results in a flush, hard cut 36because the strands of hair are immobilized in the stationary blade 18and cannot move when they are cut. It is not possible for the strands ofhair to fall into the oscillating blade 20 because the stationary blade18 has already collected and immobilized them.

FIGS. 12 and 12 a schematically depict vertically hanging strands ofhair 32 that are collected in the cutting direction 37 by a cutter head16, which has an oscillating blade 20 and a stationary blade 18. It isclear that the strands of hair 32 fall into the oscillating blade 20first. The thinned region 40 thus produced in the cut surface 34 givesthe machine cut, which has the positive inclination angle in relation tothe cut surface 34, an appearance similar to that of a scissors cutbecause the strands of hair 32 are vibrated before being cut and aretherefore unevenly collected and immobilized by the stationary blade 18before being cut.

The decisive advantage of the hair cutting machine 10 according to thepresent invention lies in the inventor's discovery that the flatter(more parallel) the cutting plane 22 of the hair cutting machine 10 isto the cut surface 34, the harder or more progressive the haircut is.This is because all of the strands of hair 32 (FIG. 13) that first fallthrough the fixed, stationary blade 18 are immobilized by it and aretherefore cut flush 36. However, if the cutting plane 22 is steeplyaligned in relation to the cut surface 34, the haircut becomes softerand therefore more harmonious. This is due to the fact that at an angleof 45° to the scalp 26, the strands of hair 32 cannot fall as deeplyinto the blades 20, 18 of the hair cutting machine 10. As a result, byexecuting a number of short movements, the stylist can be more selectiveand can better recognize whether the desired hair length L has beenreached. The hair cutting machine 10 also has the advantage that thehair cutting machine 10 is moved away 38 from the scalp 26 duringcutting, without losing the vibrating action. Consequently, thisprevents the cutting of unsightly bare patches and holes, which shouldalso be of considerable significance to first-time employees.

FIGS. 13 and 13 a schematically depict the flush cutting 36 of the hair32. It is clear that the strands of hair 32 are first immobilized by thestationary blade 18 before being cut by the oscillating blade 20. Thisproduces a flush, hard haircut 36.

FIG. 14 is an exploded view of an oscillating blade 20 and stationaryblade 18 with an eccentric drive unit 54. An electric motor 49 drives adrive shaft 41 to which an eccentric shaft 42 is attached. A metal pin43 is attached off-center to the opposite end of the eccentric shaft 42.This metal pin 43 is guided through the opening 44 in the stationaryblade 18 and inserted into a catch 45 of the oscillating blade 20. Theoscillating blade 20 and the retaining springs 46 are attached to thestationary blade 18 in a moving fashion by a parallelogram guide. Therotating motion of the eccentrically attached metal pin 43 causes theoscillating blade 20 to move back and forth since the retaining spring46 leaves the moving blade enough free play to remain mobile. The cutterhead 16 is attached to the hair cutting machine handle 12 by means of anintrinsically known snap connector system. This system of aparallelogram guide with a retaining spring 46 is intrinsically knownfrom EP0147134B1, and is held to be fully disclosed herein.

FIG. 15 shows a side view of FIG. 14.

FIG. 16 shows the assembled cutter head 16, in which the metal pin 43has been inserted through the opening 44 in the stationary blade 18,into the catch 45 of the oscillating blade 20. However, it is alsopossible for the catch 45 to be elongated so that it is guided throughthe opening 44. In lieu of the opening 44, a recess that is not shownhere can also be provided. Depending on how the metal pin 43 and thecatch 45 cooperate, it could also be possible to eliminate an opening 44or recess. In the hair cutting machine 10 with a positive angle inrelation to the longitudinal axis 24, a motor 49 sets a drive shaft 41in motion in order to drive the cutter head 16. This drive shaft 41 hasa round eccentric shaft 42 slid onto it, with a metal pin 43 attachedoff-center to the opposite side of this eccentric shaft 42. When themotor 49 is switched on, it sets this metal pin 43 into a circularmotion. In order to be able to drive the oscillating blade 20, the metalpin 43 must be guided through an opening 44 in the stationary blade 18.This opening 44 must be large enough that the moving metal pin 43 doesnot strike the stationary blade 18. The end of the metal pin 43 isinserted into the catch 45 of the oscillating blade 20. The retainingspring 46 attaches the moving blade 20 to the stationary blade 18; theretaining spring 46, however, leaves the moving blade 20 enough freeplay to allow it to move back and forth. The rotating motion of themetal pin 43 sets the oscillating blade 20 into a back-and-forthoscillation.

Because the inclination angle (Alpha) of the hair cutting machine 10 isdesigned to be adjustable, this permits it to be ergonomically adaptedto the individual. Such an adjusting device is known, for example, fromEP0147134B, for example from FIG. 30, which is held to be fullydisclosed herein.

The fact that the oscillating blade 20 is designed to be adjusted inrelation to the stationary blade 18 in the longitudinal direction 55 ofthe cutting plane 22 makes it possible to adjust the extent of thethinning 40 within certain limits.

The stationary blade 18 and the oscillating blade 20 are embodied in theform of an interchangeable cutter head 16, which permits this cutterhead 16 to be interchanged with a conventional cutter head.

Part of the oscillating blade 20 is provided with a flat covering 56,which prevents cut strands of hair 32 from being able to collect on theoscillating blade 20.

REFERENCE NUMERAL LIST

-   10 hair cutting machine-   11 lifting of the longitudinal axis-   12 handle-   12 a top-   12 b bottom-   14 handle end-   16 cutter head-   18 stationary blade (lower)-   20 oscillating blade (upper)-   22 cutting plane-   24 longitudinal axis-   26 scalp-   28 inclined cut surface-   30 cut-   31 strand of hair-   32 strands of hair-   33 curved cut surface-   34 cut surface-   36 small steps-   36 hard, flush cut surface-   37 cutting direction-   38 arc-shaped path-   39 cut-   40 minimal thinning-   41 drive shaft-   42 eccentric shaft-   43 metal pin-   44 opening in stationary blade-   45 catch-   46 retaining spring-   47 negative angle-   48 positive angle-   49 motor-   51 scissors-   52 conventional hair cutting machine-   53 cutting comb-   54 eccentric drive unit-   55 longitudinal direction-   56 covering-   L, L1, L2 hair length

1. A haircutting machine, comprising: a handle (12) with a front handleend; an electric drive unit (54) contained in the handle (12); and acutter head (16) arranged at said front handle end; wherein said cutterhead (16) comprises a stationary blade (18) and an oscillating blade(20) disposed above the stationary blade (19) in an operating positionof the handle (12) so that the stationary blade (18) and the oscillatingblade (20) define a cutting plane (22) that extends there between andthe cutting plane (22) is inclined in relation to a longitudinal axis(24) of the handle (12); wherein the cutting plane (22) encloses apositive inclination angle (α) of 0 to 90° to the longitudinal axis (24)of the handle and the oscillating blade (20) is adjustable in relationto the stationary blade (18) in a longitudinal direction (55) of thecutting plane (22); wherein the stationary blade (18) is arrangedbetween the oscillating blade (20) and the handle (12); and wherein theelectric drive unit (54) contained in the handle (12) is connected tothe oscillating blade (20) through an opening (44) provided in thestationary blade (18) in order to drive the oscillating blade.
 2. Thehair cutting machine as recited in claim 1, wherein said positiveinclination angle (α) is from 0 to 45°.
 3. The hair cutting machine asrecited in claim 1, wherein said positive inclination angle (α) is from5 to 35°.
 4. The hair cutting machine as recited in claim 1, whereinsaid positive inclination angle (α) is approximately 30°.
 5. The haircutting machine as recited in claim 1, further comprising aninterchangeable cutter head (16) comprising the stationary blade (18)and the oscillating blade (20).
 6. The hair cutting machine as recitedin claim 1, wherein the cutter head (16) comprises a flat covering (56)that covers part of the oscillating blade (20) in order to prevent cuthair strands from collecting on the oscillating blade.
 7. The haircutting machine as recited in claim 1, wherein the positive inclinationangle is adjustable.